/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.citrus.util.internal.apache.lang;

/**
 * <p>
 * 从Apache commons-lang中的同名类简化而得。
 * </p>
 * <p>
 * Assists in implementing {@link Object#equals(Object)} methods.
 * </p>
 * <p>
 * This class provides methods to build a good equals method for any class. It
 * follows rules laid out in <a
 * href="http://java.sun.com/docs/books/effective/index.html">Effective Java</a>
 * , by Joshua Bloch. In particular the rule for comparing <code>doubles</code>,
 * <code>floats</code>, and arrays can be tricky. Also, making sure that
 * <code>equals()</code> and <code>hashCode()</code> are consistent can be
 * difficult.
 * </p>
 * <p>
 * Two Objects that compare as equals must generate the same hash code, but two
 * Objects with the same hash code do not have to be equal.
 * </p>
 * <p>
 * All relevant fields should be included in the calculation of equals. Derived
 * fields may be ignored. In particular, any field used in generating a hash
 * code must be used in the equals method, and vice versa.
 * </p>
 * <p>
 * Typical use for the code is as follows:
 * </p>
 * <p/>
 * <pre>
 * public boolean equals(Object obj) {
 *     if (obj instanceof MyClass == false) {
 *         return false;
 *     }
 *     if (this == obj) {
 *         return true;
 *     }
 *     MyClass rhs = (MyClass) obj;
 *     return new EqualsBuilder().appendSuper(super.equals(obj)).append(field1, rhs.field1).append(field2, rhs.field2)
 *             .append(field3, rhs.field3).isEquals();
 * }
 * </pre>
 *
 * @author <a href="mailto:steve.downey@netfolio.com">Steve Downey</a>
 * @author Stephen Colebourne
 * @author Gary Gregory
 * @author Pete Gieser
 * @author Arun Mammen Thomas
 */
public class EqualsBuilder {
    /** If the fields tested are equals. The default value is <code>true</code>. */
    private boolean isEquals = true;

    /**
     * <p>
     * Constructor for EqualsBuilder.
     * </p>
     * <p>
     * Starts off assuming that equals is <code>true</code>.
     * </p>
     *
     * @see Object#equals(Object)
     */
    public EqualsBuilder() {
        // do nothing for now.
    }

    // -------------------------------------------------------------------------

    /**
     * <p>
     * Adds the result of <code>super.equals()</code> to this builder.
     * </p>
     *
     * @param superEquals the result of calling <code>super.equals()</code>
     * @return EqualsBuilder - used to chain calls.
     * @since 2.0
     */
    public EqualsBuilder appendSuper(boolean superEquals) {
        if (isEquals == false) {
            return this;
        }
        isEquals = superEquals;
        return this;
    }

    // -------------------------------------------------------------------------

    /**
     * <p>
     * Test if two <code>Object</code>s are equal using their
     * <code>equals</code> method.
     * </p>
     *
     * @param lhs the left hand object
     * @param rhs the right hand object
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(Object lhs, Object rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        Class<?> lhsClass = lhs.getClass();
        if (!lhsClass.isArray()) {
            // The simple case, not an array, just test the element
            isEquals = lhs.equals(rhs);
        } else if (lhs.getClass() != rhs.getClass()) {
            // Here when we compare different dimensions, for example: a boolean[][] to a boolean[]
            this.setEquals(false);
        }
        // 'Switch' on type of array, to dispatch to the correct handler
        // This handles multi dimensional arrays of the same depth
        else if (lhs instanceof long[]) {
            append((long[]) lhs, (long[]) rhs);
        } else if (lhs instanceof int[]) {
            append((int[]) lhs, (int[]) rhs);
        } else if (lhs instanceof short[]) {
            append((short[]) lhs, (short[]) rhs);
        } else if (lhs instanceof char[]) {
            append((char[]) lhs, (char[]) rhs);
        } else if (lhs instanceof byte[]) {
            append((byte[]) lhs, (byte[]) rhs);
        } else if (lhs instanceof double[]) {
            append((double[]) lhs, (double[]) rhs);
        } else if (lhs instanceof float[]) {
            append((float[]) lhs, (float[]) rhs);
        } else if (lhs instanceof boolean[]) {
            append((boolean[]) lhs, (boolean[]) rhs);
        } else {
            // Not an array of primitives
            append((Object[]) lhs, (Object[]) rhs);
        }
        return this;
    }

    /**
     * <p>
     * Test if two <code>long</code> s are equal.
     * </p>
     *
     * @param lhs the left hand <code>long</code>
     * @param rhs the right hand <code>long</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(long lhs, long rhs) {
        if (isEquals == false) {
            return this;
        }
        isEquals = lhs == rhs;
        return this;
    }

    /**
     * <p>
     * Test if two <code>int</code>s are equal.
     * </p>
     *
     * @param lhs the left hand <code>int</code>
     * @param rhs the right hand <code>int</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(int lhs, int rhs) {
        if (isEquals == false) {
            return this;
        }
        isEquals = lhs == rhs;
        return this;
    }

    /**
     * <p>
     * Test if two <code>short</code>s are equal.
     * </p>
     *
     * @param lhs the left hand <code>short</code>
     * @param rhs the right hand <code>short</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(short lhs, short rhs) {
        if (isEquals == false) {
            return this;
        }
        isEquals = lhs == rhs;
        return this;
    }

    /**
     * <p>
     * Test if two <code>char</code>s are equal.
     * </p>
     *
     * @param lhs the left hand <code>char</code>
     * @param rhs the right hand <code>char</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(char lhs, char rhs) {
        if (isEquals == false) {
            return this;
        }
        isEquals = lhs == rhs;
        return this;
    }

    /**
     * <p>
     * Test if two <code>byte</code>s are equal.
     * </p>
     *
     * @param lhs the left hand <code>byte</code>
     * @param rhs the right hand <code>byte</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(byte lhs, byte rhs) {
        if (isEquals == false) {
            return this;
        }
        isEquals = lhs == rhs;
        return this;
    }

    /**
     * <p>
     * Test if two <code>double</code>s are equal by testing that the pattern of
     * bits returned by <code>doubleToLong</code> are equal.
     * </p>
     * <p>
     * This handles NaNs, Infinities, and <code>-0.0</code>.
     * </p>
     * <p>
     * It is compatible with the hash code generated by
     * <code>HashCodeBuilder</code>.
     * </p>
     *
     * @param lhs the left hand <code>double</code>
     * @param rhs the right hand <code>double</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(double lhs, double rhs) {
        if (isEquals == false) {
            return this;
        }
        return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
    }

    /**
     * <p>
     * Test if two <code>float</code>s are equal byt testing that the pattern of
     * bits returned by doubleToLong are equal.
     * </p>
     * <p>
     * This handles NaNs, Infinities, and <code>-0.0</code>.
     * </p>
     * <p>
     * It is compatible with the hash code generated by
     * <code>HashCodeBuilder</code>.
     * </p>
     *
     * @param lhs the left hand <code>float</code>
     * @param rhs the right hand <code>float</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(float lhs, float rhs) {
        if (isEquals == false) {
            return this;
        }
        return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
    }

    /**
     * <p>
     * Test if two <code>booleans</code>s are equal.
     * </p>
     *
     * @param lhs the left hand <code>boolean</code>
     * @param rhs the right hand <code>boolean</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(boolean lhs, boolean rhs) {
        if (isEquals == false) {
            return this;
        }
        isEquals = lhs == rhs;
        return this;
    }

    /**
     * <p>
     * Performs a deep comparison of two <code>Object</code> arrays.
     * </p>
     * <p>
     * This also will be called for the top level of multi-dimensional, ragged,
     * and multi-typed arrays.
     * </p>
     *
     * @param lhs the left hand <code>Object[]</code>
     * @param rhs the right hand <code>Object[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(Object[] lhs, Object[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>long</code>. Length and all values are
     * compared.
     * </p>
     * <p>
     * The method {@link #append(long, long)} is used.
     * </p>
     *
     * @param lhs the left hand <code>long[]</code>
     * @param rhs the right hand <code>long[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(long[] lhs, long[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>int</code>. Length and all values are
     * compared.
     * </p>
     * <p>
     * The method {@link #append(int, int)} is used.
     * </p>
     *
     * @param lhs the left hand <code>int[]</code>
     * @param rhs the right hand <code>int[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(int[] lhs, int[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>short</code>. Length and all values are
     * compared.
     * </p>
     * <p>
     * The method {@link #append(short, short)} is used.
     * </p>
     *
     * @param lhs the left hand <code>short[]</code>
     * @param rhs the right hand <code>short[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(short[] lhs, short[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>char</code>. Length and all values are
     * compared.
     * </p>
     * <p>
     * The method {@link #append(char, char)} is used.
     * </p>
     *
     * @param lhs the left hand <code>char[]</code>
     * @param rhs the right hand <code>char[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(char[] lhs, char[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>byte</code>. Length and all values are
     * compared.
     * </p>
     * <p>
     * The method {@link #append(byte, byte)} is used.
     * </p>
     *
     * @param lhs the left hand <code>byte[]</code>
     * @param rhs the right hand <code>byte[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(byte[] lhs, byte[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>double</code>. Length and all values
     * are compared.
     * </p>
     * <p>
     * The method {@link #append(double, double)} is used.
     * </p>
     *
     * @param lhs the left hand <code>double[]</code>
     * @param rhs the right hand <code>double[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(double[] lhs, double[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>float</code>. Length and all values are
     * compared.
     * </p>
     * <p>
     * The method {@link #append(float, float)} is used.
     * </p>
     *
     * @param lhs the left hand <code>float[]</code>
     * @param rhs the right hand <code>float[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(float[] lhs, float[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Deep comparison of array of <code>boolean</code>. Length and all values
     * are compared.
     * </p>
     * <p>
     * The method {@link #append(boolean, boolean)} is used.
     * </p>
     *
     * @param lhs the left hand <code>boolean[]</code>
     * @param rhs the right hand <code>boolean[]</code>
     * @return EqualsBuilder - used to chain calls.
     */
    public EqualsBuilder append(boolean[] lhs, boolean[] rhs) {
        if (isEquals == false) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null || rhs == null) {
            this.setEquals(false);
            return this;
        }
        if (lhs.length != rhs.length) {
            this.setEquals(false);
            return this;
        }
        for (int i = 0; i < lhs.length && isEquals; ++i) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Returns <code>true</code> if the fields that have been checked are all
     * equal.
     * </p>
     *
     * @return boolean
     */
    public boolean isEquals() {
        return this.isEquals;
    }

    /**
     * Sets the <code>isEquals</code> value.
     *
     * @param isEquals The value to set.
     * @since 2.1
     */
    protected void setEquals(boolean isEquals) {
        this.isEquals = isEquals;
    }
}
